libdiskmgt/common/inuse_fs.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

#include <dirent.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <synch.h>
#include <unistd.h>
#include <sys/errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/vfstab.h>
#include <fcntl.h>
#include <sys/wait.h>
#include <sys/fs/ufs_fs.h>

#include "libdiskmgt.h"
#include "disks_private.h"

/*
 * The list of filesystem heuristic programs.
 */
struct heuristic {
    struct heuristic    *next;
    char            *prog;
    char            *type;
};

struct vfstab_list {
    char    *special;
    char    *mountp;
    struct vfstab_list  *next;
};

static struct vfstab_list   *vfstab_listp = NULL;
static  mutex_t vfstab_lock = DEFAULTMUTEX;

static  time_t  timestamp = 0;

static struct heuristic *hlist = NULL;
static int      initialized = 0;
static mutex_t      init_lock = DEFAULTMUTEX;

static int  has_fs(char *prog, char *slice);
static int  load_heuristics();
static int  add_use_record(struct vfstab *vp);
static int  load_vfstab();
static void free_vfstab(struct vfstab_list *listp);

/*
 * Use the heuristics to check for a filesystem on the slice.
 */
int
inuse_fs(char *slice, nvlist_t *attrs, int *errp)
{
    struct  heuristic   *hp;
    time_t  curr_time;
    int found = 0;


    *errp = 0;

    if (slice == NULL) {
        return (0);
    }

    /*
     * We get the list of heuristic programs one time.
     */
    (void) mutex_lock(&init_lock);
    if (!initialized) {
        *errp = load_heuristics();

        if (*errp == 0) {
        initialized = 1;
        }
    }
    (void) mutex_unlock(&init_lock);

    /* Run each of the heuristics. */
    for (hp = hlist; hp; hp = hp->next) {
        if (has_fs(hp->prog, slice)) {
        libdiskmgt_add_str(attrs, DM_USED_BY, DM_USE_FS, errp);
        libdiskmgt_add_str(attrs, DM_USED_NAME, hp->type, errp);
        found = 1;
        }
    }

    if (*errp != 0)
        return (found);

    /*
     * Second heuristic used is the check for an entry in vfstab
     */

    (void) mutex_lock(&vfstab_lock);
    curr_time = time(NULL);

    if (timestamp < curr_time && (curr_time - timestamp) > 60) {
        free_vfstab(vfstab_listp);
        *errp = load_vfstab();
        timestamp = curr_time;
    }

    if (*errp == 0) {
        struct vfstab_list  *listp;
        listp = vfstab_listp;

        while (listp != NULL) {
        if (strcmp(slice, listp->special) == 0) {
            char *mountp = "";

            if (listp->mountp != NULL)
            mountp = listp->mountp;

            libdiskmgt_add_str(attrs, DM_USED_BY, DM_USE_VFSTAB, errp);
            libdiskmgt_add_str(attrs, DM_USED_NAME, mountp, errp);
            found = 1;
        }
        listp = listp->next;
        }
    }
    (void) mutex_unlock(&vfstab_lock);
    return (found);
}

static int
has_fs(char *prog, char *slice)
{
    pid_t   pid;
    int loc;
    mode_t  mode = S_IRUSR | S_IWUSR;

    switch ((pid = fork1())) {
    case 0:
        /* child process */

        closefrom(1);
        (void) open("/dev/null", O_WRONLY, mode);
        (void) open("/dev/null", O_WRONLY, mode);
        (void) execl(prog, "fstyp", slice, NULL);
        _exit(1);
        break;

    case -1:
        return (0);

    default:
        /* parent process */
        break;
    }

    (void) waitpid(pid, &loc, 0);

    if (WIFEXITED(loc) && WEXITSTATUS(loc) == 0) {
        return (1);
    }

    return (0);
}

/*
 * Create a list of filesystem heuristic programs.
 */
static int
load_heuristics()
{
    DIR *dirp;

    if ((dirp = opendir("/usr/lib/fs")) != NULL) {
        struct dirent   *dp;

        while ((dp = readdir(dirp)) != NULL) {
        char        path[MAXPATHLEN];
        struct stat buf;
        DIR     *subdirp;

        /* skip known dirs */
        if (strcmp(dp->d_name, ".") == 0 ||
            strcmp(dp->d_name, "..") == 0) {
            continue;
        }

        /*
         * Skip checking for ZFS filesystems.  We know that
         * inuse_zpool() will have already been called, which does a
         * better job of checking anyway.  More importantly, an unused
         * hot spare will still claim to have a ZFS filesystem because
         * it doesn't do the same level of checks.
         */
        if (strcmp(dp->d_name, "zfs") == 0)
            continue;

        (void) snprintf(path, sizeof (path), "/usr/lib/fs/%s",
            dp->d_name);

        if (stat(path, &buf) != 0 || !S_ISDIR(buf.st_mode)) {
            continue;
        }

        if ((subdirp = opendir(path)) != NULL) {
            struct dirent   *sdp;

            while ((sdp = readdir(subdirp)) != NULL) {

            if (strcmp(sdp->d_name, "fstyp") == 0) {
                char progpath[MAXPATHLEN];

                (void) snprintf(progpath, sizeof (progpath),
                "/usr/lib/fs/%s/fstyp", dp->d_name);

                if (stat(progpath, &buf) == 0 &&
                S_ISREG(buf.st_mode)) {

                struct heuristic *hp;

                hp = (struct heuristic *)
                    malloc(sizeof (struct heuristic));

                if (hp == NULL) {
                    (void) closedir(subdirp);
                    (void) closedir(dirp);
                    return (ENOMEM);
                }

                if ((hp->prog = strdup(progpath)) == NULL) {
                    (void) closedir(subdirp);
                    (void) closedir(dirp);
                    return (ENOMEM);
                }

                if ((hp->type = strdup(dp->d_name)) == NULL) {
                    (void) closedir(subdirp);
                    (void) closedir(dirp);
                    return (ENOMEM);
                }

                hp->next = hlist;
                hlist = hp;
                }

                break;
            }
            }

            (void) closedir(subdirp);
        }
        }

        (void) closedir(dirp);
    }

    return (0);
}

static int
load_vfstab()
{
    FILE    *fp;
    struct  vfstab vp;
    int status = 1;

    fp = fopen(VFSTAB, "r");
    if (fp != NULL) {
        (void) memset(&vp, 0, sizeof (struct vfstab));
        while (getvfsent(fp, &vp) == 0) {
            status = add_use_record(&vp);
            if (status != 0) {
            (void) fclose(fp);
            return (status);
            }
        (void) memset(&vp, 0, sizeof (struct vfstab));
        }
        (void) fclose(fp);
        status = 0;
    }

    return (status);
}

static int
add_use_record(struct vfstab *vp)
{
    struct  vfstab_list *vfsp;

    vfsp = (struct vfstab_list *)malloc(sizeof (struct vfstab_list));
    if (vfsp == NULL) {
        return (ENOMEM);
    }

    vfsp->special = strdup(vp->vfs_special);
    if (vfsp->special == NULL) {
        free(vfsp);
        return (ENOMEM);
    }

    if (vp->vfs_mountp != NULL) {
        vfsp->mountp = strdup(vp->vfs_mountp);
        if (vfsp->mountp == NULL) {
        free(vfsp);
        return (ENOMEM);
        }
    } else {
        vfsp->mountp = NULL;
    }

    vfsp->next = vfstab_listp;
    vfstab_listp = vfsp;

    return (0);
}

static void
free_vfstab(struct vfstab_list *listp)
{
    struct vfstab_list  *nextp;

    while (listp != NULL) {
        nextp = listp->next;
        free((void *)listp->special);
        free((void *)listp->mountp);
        free((void *)listp);
        listp = nextp;
    }

    vfstab_listp = NULL;
}